The present invention relates generally to medical devices and methods. More specifically, the invention relates to devices and methods that for performing a function in a gastrointestinal tract.
Obesity has become a medical problem of epidemic proportions in the United States. Recent governmental studies estimate that as many as 40% of Americans are obese (defined as a Body Mass Index over 30), and of those, almost 20% are morbidly obese. Unfortunately, there is no indication that these percentages will decrease and every indication that they will increase in the coming years. Studies have linked obesity to countless health risks, a small sampling of which includes cardiovascular disease, cancer, diabetes, orthopedic injuries and complaints, obstructive sleep apnea, chronic fatigue and depression. Despite billions of dollars spent searching for obesity cures, conducting research into nutrition and exercise, and educating the public about obesity, efforts to date have been largely ineffective.
Many Americans have tried combating obesity with diet, exercise and even medications, to no avail. Most people who lose weight through diet and exercise gain it back again in a short period of time. Available medications can have serious side effects, as was evidenced by the recent scare with the Fen-Phen dietary medication. Faced with the difficulty of diet and exercise, nutritional information that seems to change radically and rapidly, and diet medications and supplements that typically do not work and may cause serious side effects, many obese people become frustrated and either decide to remain obese or choose to pursue a more drastic treatment option.
The more drastic options typically involve surgical procedures, such as stomach stapling, other gastric reduction surgical techniques, placement of a constrictive band around the outside of the stomach, and gastic bypass. The most well known procedure, in part due to well-publicized experiences of celebrities like Al Roker and Carney Wilson, is the gastric bypass operation, known technically as a Roux-En-Y gastric bypass. In this procedure, the stomach is actually bypassed, and a very small stomach-like pouch remains, making a patient feel full after ingesting a small amount of food. Although gastric bypass can be highly effective, it is acknowledged to be a very high-risk operation, with a 1-2% mortality rate, a number of possible complications such as digestive problems, and a recovery period of up to 6 months. The other surgical alternatives are also associated with either high risk, low rate of effectiveness, or both.
Stemming from the high risks of gastric surgical procedures and the ineffectiveness of diet and exercise for many obese people, a number of medical devices have been developed to address weight loss and obesity, but these too have numerous drawbacks. Some devices, for example, try to bypass a portion of the stomach or small intestine by essentially creating a tube or chute through which food passes without any nutrients or calories being absorbed. Such devices are described, for example, in U.S. Pat. No. 5,820,584 and U.S. patent application Publication Nos. 2003/0040804 and 2003/0109931. Other techniques involve placing space-occupying balloons and other devices within the stomach to make the patient feel full after eating small amounts of food. One such a device, for example, is described in U.S. patent application Publication No. 2003/0109935.
One significant drawback of currently available devices such as absorption-reducing gastrointestinal sleeves and space occupying gastric balloons is that they are directly attached to the wall of the gastrointestinal tract. Such direct attachment may often lead to erosion and ulceration of the lining of the stomach or small intestine. Another significant risk with currently available devices is that if the direct attachment to gastrointestinal tissue fails for some reason, the device may pass through the pyloric valve of the stomach and into the small intestine. From there, the device may cause a blockage in the small or large intestine, which typically requires surgery and may be fatal if discovered too late.
Another approach for obesity treatment, as described, for example, in U.S. patent application Publication No. 2003/0093117, involves performing a minimally invasive surgical procedure on a stomach, typically to reduce its volume. Yet another approach involves severing or stimulating the vagus nerve in an attempt to slow the rate at which food passes from the stomach into the duodenum. Others have tried slowing gastric emptying by placing implants or injecting bulking agents into tissue at or immediately adjacent the pyloric valve. Such techniques are described, for example, in U.S. Pat. No. 6,540,789 and U.S. patent application Publication Nos. 2003/0153806 and 2003/0158601. In general, all of these types of therapies require invasive, sometimes irreversible, surgical procedures, risking a number of potential serious side effects to the functioning of the gastrointestinal tract.
Of course, obesity is not the only health problem associated with the gastrointestinal tract. It is offered here merely as an example of one serious gastrointestinal-related health problem without an ideal means of treatment or cure. Many other health conditions are caused or directly related to functioning of the gastrointestinal tract, and like obesity, many such conditions do not currently have optimal medical or surgical treatments.
Therefore, a need exists for effective, minimally-invasive or non-invasive devices and methods for obesity and other conditions related to the gastrointestinal tract. Ideally, such devices and methods would be relatively easy to use and deploy in a patient and would help treat obesity and/or other conditions without a high risk of side effects or severe complications. Ideally, such devices and methods would also be reversible and/or capable of being modified via external devices or minimally invasive means. At least some of these objectives will be met by the present invention.